1. Field of the Invention
The present invention relates to an image processing device, an image processing method and a storage medium storing an image processing program which execute reduction processing on distortion such as flicker included in an image.
2. Related Background of the Invention
“Picture” is formed by continuously using “frame images”, each of which is a single still image. Picture processing including the acquisition, transmission, compression (encoding and decoding), reduction and enlargement of picture generally causes various types of distortion. Therefore, it is a great challenge to reduce the distortion in the picture processing.
On the other hand, cameras have recently been incorporated in mobile terminals such as cell phones and, as the speed of mobile communication networks is increased, users increasingly watch downloaded picture with mobile terminals. Distortion caused by picture processing will now be described below using an example of a mobile terminal.
Since it is generally required to reduce the size and the power consumption of a mobile terminal, a camera incorporated in the mobile terminal has limited functions as compared with normal separate cameras. Thus, picture taken by the camera incorporated in the mobile terminal may include mosquito noise and flicker. Further, in the distribution of picture through mobile communication networks, it is common to execute compression processing on picture data from the standpoint of effectively utilizing a transmission band. Hence, the picture often includes flicker, block distortion, aliasing distortion and ringing distortion.
Different distortions included in the picture often lead directly to the evaluation of image quality; and it is needless to say that picture having less distortion is evaluated as having higher quality.    [Non-patent reference 1] “New Edition Sensation/Perception Psychology Handbook” written by Tadashi Oyama, Shogo Imai and Wake Tenji, published by Seishin Shobo, ISBN; 441-4305039, p, 583